Heatstroke

What is heatstroke?

Heatstroke can be a life-threatening condition, requiring
urgent medical attention.

Heatstroke is a condition in which the brain’s normal heat
regulation system fails and the body becomes overheated in a relatively short
space of time.

This can be a life-threatening condition, requiring urgent
medical attention. Some soldiers on training have died from this condition. (In
2013 there were sadly three deaths in the Brecon Beacons.)

Abnormally high body temperatures (hyperthermia) may occur in
several different circumstances, such as:

classic heatstroke (also called sunstroke: a little misleading
because the condition can arise without the direct effect of the sun) when,
typically, the skin is flushed, red and dry

heatstroke caused by exertion, which often occurs in
conjunction with pronounced physical exertion, eg sports activity

in extensive
burns (including
sunburn), where the sweat glands have been damaged or destroyed

in a number of less common medical conditions, such as over
activity of the thyroid gland (thyrotoxicosis).

The first three in the list are of special interest to the
traveller.

When can heatstroke occur?

Heatstroke occurs when the body cannot dispose of excess heat in
the normal way.

Heatstroke and fever can be distinguished as follows:

fever, in which the body's mechanism for regulating temperature
is functioning and set at a higher level. The patient is, typically, flushed
and bathed in sweat.

primary hyperthermia (for instance, heatstroke), where
temperature regulation is either partially or totally out of action. The
patient often sweats only a little or not at all, and the skin is flushed red,
hot and dry.

What puts the traveller at risk of suffering heatstroke?

Surroundings with high temperature, high humidity and strong
sunlight (typically in the tropics).

What can you do to help yourself?

It's important to get used to heat and humidity slowly,
particularly before physical exertion. This acclimatisation to the tropics can
typically take one to three weeks.

Make sure you drink plenty of sugar and salt liquids (at least
3 to 5 litres a day, but not alcohol). In very hot conditions you may need to
drink much more and a good tip is to start the day by drinking at least two
litres!

Military and extreme sports specialists should consider testing
their sodium excretion since this can vary eightfold and hence there is an
eightfold variation in how much sodium needs to be replaced.

Wear light, airy, loose-fitting clothing (light cotton).

Be careful if you undertake any hard physical exertion,
particularly if your fluid/salt intake is low.

Stay in the shade or, if possible, in an air-conditioned
environment.

Take frequent dips in cool water (sea or pool), particularly if
you are sunbathing a lot.

When does heatstroke become critical?

Body temperature around 41°C (measured in the rectum).

You feel increasingly unwell, tired and dizzy, and your head
may hurt and you may feel 'distant'.

You may feel cold, despite the heat and this a very worrying
symptom.

If your skin becomes flushed red and dry (ie perspiration is
reduced or not functioning).

You produce less urine, which is of a dark yellowish colour
(which indicates a shortage of fluid).

You become less alert, with a tendency to faint, and experience
confusion, impairment or loss of consciousness and convulsions.

At temperatures above 41°C the situation starts to be serious.
At temperatures above 42°C cell damage to the brain, liver, kidneys and
skeletal muscle often occurs as well as bleeding disorders.

Therapy

If a person suffers from heatstroke, it's important to put them
in the shade and preferably in a cool environment (ideally an air-conditioned
room at a temperature of 15 to 18°C).

The patient should be undressed, with sensitivity, or covered
only by a thin sheet.

If the patient's temperature rises to 39.5°C and the skin is
still dry and burning hot (or with only very slight sweating), they should be
showered with cool water (15 to 18°C). You can also put the person in a bath of
cool water, while massaging the skin to increase circulation. Another
possibility is to cover the patient with wet sheets or towelling, changing them
often, preferably in combination with an electric fan, or something similar, to
bring the temperature further down.

Do not use water cooler than 15°C because this will restrict
heat loss because the blood vessels in the skin will contract.

If possible, the patient should be taken to a doctor, or better
still a hospital, as soon as possible. A person with heatstroke often needs
oxygen, a drip (fluid infusion into a vein) and sometimes medication.

The materials in this web site are in no way intended to replace the professional medical care, advice, diagnosis or treatment of a doctor. The web site does not have answers to all problems. Answers to specific problems may not apply to everyone. If you notice medical symptoms or feel ill, you should consult your doctor - for further information see our Terms and conditions.